Description of local environment

Air quality

There are no Air Quality Management Areas (AQMA), registered sites on the Scottish Pollutant Release Inventory (SPRI), or any Air Quality Monitoring Stations (AQMS) located within 10km of the scheme.

Due to the rural location of the scheme, baseline air quality is likely to be primarily influenced by traffic along the nearby A9 trunk road and Highland Mainline Railway. Secondary sources are likely derived from land management and coastal activities.

Cultural heritage

The Mound Sluices bridge is designated under the following cultural heritage classifications (PastMap):

  • Category A Listed Building: ‘Mound Bridge and Keeper’s Cottage’ (LB7022). The Keeper’s Cottage lies approximately 20m east of Mound Bridge and, of lesser cultural heritage significance, is also listed as a National Record of the Historic Environment (NRHE).
  • NRHE: ‘The Mound’ (Ref: 14787)
  • Historical Environment Record (HER): ‘Mound Bridge, Loch Fleet’ (Ref: MHG45526)

Of lesser cultural heritage interest, there are 3 other NRHE within 300m of the scheme, the closest of which is The Mound, Station, 120m southeast. There are 7 HERs within 300m of the scheme, the closest of which is The Mound Causeway directly west of the Mound Bridge (PastMap).

There are no Conservation Areas, Battlefields, World Heritage Sites, Gardens and Designed Landscapes, or Scheduled Monuments within 300m of the scheme extent (PastMap).

Landscape and visual effects

The scheme is not located in a National Park, National Scenic Area or any other site designated for its landscape character or quality (SiteLink).

The scheme is located on the boundary between a ‘Coastal Farmland and Woodlands 146’ Landscape Character Type (LCT); and a ‘Strath-Caithness and Sutherland 142’ LCT (SNH National Landscape Character Assessment).

LCT ‘Coastal Farmland and Woodlands- 146’ is classified by the following key characteristics:

  • Rolling landform to the west within the Dornoch Firth where this landscape tapers and is constrained to the north by a steep-sided densely wooded ridge.
  • Gently undulating landform to the east of Skibo and Loch Fleet.
  • Flat or gently sloping plain north of Loch Fleet.
  • Well-wooded landscape with coniferous forests, often fringed by broadleaf trees, planted on steeper slopes and capping small ridges and knolls on the shores of the Dornoch Firth in the west.
  • Policy plantings associated with estates with areas of parkland, tree avenues and ornamental plantings of broadleaves and tall conifers. Plantings of beech common along roadsides on northern lower slopes of Dornoch Firth, with a strong geometric framework of woodlands and mature trees contain large fields in this area.
  • Medium to large fields of fertile soils, with a high proportion of arable cropping in some areas.
  • Large castles, estate buildings and grand houses on the shores of the Dornoch Firth, as well as the visually prominent and architecturally distinct Dunrobin Castle on the coast north of Golspie, whose turrets and grand tree-lined avenue can be seen from the A9, as well as its lodges, gatehouses and buildings in and around Golspie associated with the Sutherland Estate.
  • Dispersed farms throughout the area and occasional clusters of crofts, often on the edge of woodland and associated with smaller pastures on higher slopes at the transition with the Farmed and Forested Slopes with Crofts or close to the coast at Skelbo.
  • High visibility from the east coast railway and coastal trunk roads, as well as the network of other roads which cross this area.

LCT ‘Strath-Caithness and Sutherland-142’ is classified by the following key characteristics:

  • Straths range from fairly straight deeply incised troughs to more winding valleys with a number of minor side glens.
  • River terraces and hummocky lower side slopes a common feature.
  • Water is a key characteristic with straths accommodating a central river meandering across the floodplain, often traced by clumps of birch and alder.
  • Lochs in some straths, where a string of small lochs add to the scenic richness of the lower strath.
  • Areas of wetland often present on the strath floors.
  • Smooth and fairly large pastures the predominant land cover on the floodplains of the straths, commonly enclosed by wire fences.
  • Semi-improved pastures, heather and grass moorland and coniferous plantations covering lower side slopes.
  • Increasing extent of moorland and woodland generally further up the straths, where the floodplain narrows and settlement is sparser.
  • Smaller strip-fields present on often hummocky, lower side slopes and associated with croft houses arranged in linear groups raised on terraces above the floodplain and sometimes backed by woodland.
  • Some crofts within the Straths more randomly dispersed or staggered on lower hill slopes.
  • Occasional small farms located in the broader and more fertile parts of the straths.
  • Settlement generally denser within the lower reaches of many straths, especially at bridging points, on the coast and close to major roads.
  • Many areas rich in archaeology with cairns, roundhouses, brochs and old field systems, usually found on side slopes.
  • Abandoned crofts, particularly within the upper straths and in narrow side glens.
  • Focus on views from roads provided by a number of estate shooting lodges, and clustered, predominantly 19th Century, often estate style buildings.
  • Narrow roads, commonly aligned along the edge of the floodplain, from which views are strongly channelled by the side slopes.
  • Rounded Hills often forming prominent edges to the straths with shapely well-defined hills, providing a distinctive skyline and scenic backdrop.
  • Highly scenic backdrop of mountains often revealed in some of the upper reaches of these straths.

Land use surrounding the scheme extent is classified as reservoir; managed woodland; plantation; and rough grazing (HLA Map).

The A9 Mound Sluices forms a historical part of A9 causeway over Loch Fleet separating the River Fleet from the sea, south of Golspie. Land surrounding the area is dominated by marine habitats, inland surface waters and a variety of woodland types.

The A9 trunk road bridge lies parallel to the A9 Mound Sluices (25m south-east) and forms a major landscape feature in the area. A9 Mound Sluices forms a structure associated with the A9 infrastructure which is utilised by local residents and tourists however it does not form a part of the A9 carriageway.

Biodiversity

The A9 Mound Sluices lies within the Dornoch Firth and Loch Fleet Special Protection Area (SPA) (Site ID: 8490).

The Mound Alderwoods Special Area of Conservation (SAC) (Site ID: 8332) lies 55m northwest of the scheme.

The Dornoch Firth and Loch Fleet Ramsar (Site ID: 8420) overlaps the Dornoch Firth and Loch Fleet SPA and Mound Alderwoods SAC.

The Dornoch Firth and Loch Fleet SPA is also overlapped by the Loch Fleet Site of Special Scientific Interest (SSSI) (Site ID: 984).

The Mound Alderwoods SAC is overlapped by the Mound Alderwoods SSSI (Site ID: 1202).

In addition, the A9 Mound Sluices scheme is located within the Loch Fleet National Nature Reserve (NNR) (Site ID: 5073) and is designated for a variety of coastal and forest habitats and associated wildlife. It is also located within the Loch Fleet and Dornoch and Cuthill Sands Nature Conservation Order (NCO) 1995.

The National Biodiversity Network (NBN) Atlas holds multiple records of bird species within 2km of the scheme (the search criteria included only records during the past ten years, and which have open-use attributions (OGL-CC0-CC-BY). Under the Wildlife and Countryside Act 1981 (as amended), all wild birds and their active nests are protected, with certain species receiving additional protections.

The NBN Atlas holds the following records of invasive non-native species (INNS) (as denoted by *) and native invasive perennials (as listed in the Network Management Contract (NMC)) under the same search criteria:

  • Rosebay willowherb (Chamerion angustifolium)
  • Rhododendron (Rhododendron ponticum) *

A search using Transport Scotland’s Asset Management Performance System (AMPS) has highlighted no records of INNS within 300m of the scheme extent. 

Habitat in the surrounding area is dominated by marine and coastal habitats, freshwater and mixed woodland. Woodland in proximity to the scheme is a prevalent landscape feature with the majority classified as native woodland (Native Woodland Survey of Scotland) containing a variety of open ground, native trees and shrubs.

Aquatic habitats in proximity to the scheme are present within Loch Fleet and the River Fleet. Habitats at the scheme extent are characterised by brackish water due to the saline and freshwater mix which creates a unique ecosystem.

There are several areas of ancient woodland as listed on the Ancient Woodland Inventory (AWI) within 300m of the scheme. The closest of these is Wood ID 6612 of long-established (of plantation origin) approximately 60m east of the scheme.

There are no areas of trees covered by a Tree Preservation Order (TPO) by Highland Council within 300m of the scheme extents.

Various ecological surveys have been conducted for this structure from 2020 to 2026.

Geology and soils

The scheme does not lie within proximity to a Geological Conservation Review Site (GCRS) or a SSSI designated for geological features (NatureScot).

Component soils around the scheme extent are described as ‘Humus-iron podzols’. The parent material is described as ‘drifts derived from Middle Old Red Sandstone Barren Group sandstones and conglomerates’ (Scotland’s Soils).

Soils in the area immediately surrounding the scheme extent are Class 0 mineral soils; peatland habitats are not typically found on such soils (Carbon and Peatland Map 2016).

Bedrock geology within the scheme extent is described as ‘Langwell Conglomerate Member’. Superficial deposits immediately surrounding the scheme to the north and east are ‘Raised Marine Deposits, Devensian (gravel, sand and silt)’. These sedimentary superficial deposits were formed between 116 and 11.8 thousand years ago during the Quaternary period. Superficial deposits to the south and west of the scheme are ‘Marine Beach Deposits (gravel, sand and silt)’. These sedimentary superficial deposits were formed between 2.588 million years ago and the present during the Quaternary period (British Geological Society).

Material assets and waste

The A9 Mound Sluices refurbishment works are required following inspections which identified a number of maintenance issues on the bridge, including that several of the sluice gates within the structure were no longer watertight. The timberwork has reached the end of its working life and needs to be replaced. Materials required for works in 2026 include:

  • Timber for sluice gates
  • Galvanised steel framing
  • Bracketry and fixings
  • Rubber seals

Removed, life-expired timber, rubber and corroded steel from the old gates and framework is expected to be generated as waste on site during refurbishment works and will be disposed of appropriately.

A Site Waste Management Plan (SWMP) is required as the scheme value exceeds £350,000.

Noise and vibration

For residential, community and commercial receptors refer to the ‘Population and Human Health’ section below.

The works do not fall within a Candidate Noise Management Area (CNMA) as defined by Transport Scotland’s Transport Noise Action Plan (TNAP) 2024 to 2028.

Noise levels at the scheme extent for day, evening and night (LDEN) fall around 59dB, with noise levels on the nearby A9 reaching up to 71dB (SpatialData.gov.scot).

Baseline noise levels are likely to be primarily influenced by traffic travelling along the nearby A9.

Population and human health

The scheme is located adjacent to the A9 5.3km south of Golspie in a small hamlet containing 3 residential properties, the closest at a distance of 20m north of the scheme with no acoustic or visual screening present. There is one other residential property and ‘Beech Tree Lodge B&B’ approximately 160m north of the scheme; however, these are screened by woodland.

There is a Highland Council public car park 25m west of the scheme which is a popular spot for visitors, birdwatchers and campers, with several picnic tables surrounding this. It is expected that this car park will be closed for the duration of the works to allow for a site compound, in agreement with the Highland Council. The junction leading onto the A9 lies 100m southwest of the scheme.

The Mound Bridge is a single-track road used by vehicles, non-motorised road users (NMUs) and pedestrians and acts as local access to the 3 residential properties.

The Highland Mainline Railway lies approximately 40m east of the scheme at its closest point.

There are no bus stops or National Cycle Routes within 300m of the scheme extent.

There are no Core Paths or walking routes as recorded by Walk Highlands within 300m of the scheme.

There is no requirement for TM on the main A9 carriageway and local access across A9 Mound Sluices will be maintained.

Road drainage and the water environment

Loch Fleet is a coastal water body (ID: 200475) in the Scotland river basin district. It is 6.7 square kilometres in area and lies directly south of the Mound Bridge. Loch Fleet has been designated as a heavily modified water body on account of physical alterations that cannot be addressed without a significant impact on an airport or major transport route and protected habitats and species. Loch Fleet at its coastal section is protected with the following designations: Loch Fleet and Dornoch and Cuthill Sands NCO 1995; Dornoch Firth and Loch Fleet Ramsar; Loch Fleet SSSI; and the Dornoch Firth and Loch Fleet SPA. Full details of these designations can be found in the Biodiversity section above. In 2024, Loch Fleet was assigned ‘Good Ecological Potential’ by the Scottish Environment Protection Agency (SEPA) under the Water Framework Directive 2000/60/EC (WFD) (SEPA).

Loch Fleet Mainland is a coastal water body (ID: 200331) in the Scotland river basin district. It is 0.1 square kilometres in area and lies directly northwest of the A9 Mound Sluices. Loch Fleet Mainland is protected with the following designations: Dornoch Firth and Loch Fleet Ramsar; Mound Alderwoods SAC; Dornoch Firth and Loch Fleet SPA; and Mound Alderwoods SSSI. Full details of these designations can be found in the Biodiversity section above. In 2024, Loch Fleet Mainland was assigned a classification of ‘Good Ecological Potential’ by SEPA under the WFD (SEPA).

River Fleet (Loch Fleet to Rogart section) is a river (ID: 23390), in the River Fleet catchment of the Scotland river basin district. The main stem is approximately 7.7 kilometres in length, and it lies approximately 220m north of the Mound Bridge with hydrological connectivity via the Loch Fleet Mainland waterbody. The river has been designated as a heavily modified water body on account of physical alterations that cannot be addressed without a significant impact on the drainage of agricultural land. In 2024, it was assigned ‘Moderate Ecological Potential’ by SEPA under the WFD (SEPA).

The area surrounding the scheme is covered by the Dornoch (ID: 150544) and Brora (ID: 150703) groundwater bodies, which were both assigned ‘Good Ecological Potential’ by SEPA under the WFD in 2024 (SEPA). These groundwaters are also drinking water protected areas (Scottish Government).

There are several other unclassified water bodies, drains, springs and wetlands within 300m of the scheme.

SEPA Flood Map has highlighted a high risk of river water flooding around the north of Mound Bridge (i.e. a 10% chance of flooding each year). It has also highlighted a medium to high risk of coastal flooding surrounding the scheme extent (i.e. a 0.5-10% chance of flooding each year).

Climate

The Climate Change (Scotland) Act 2009 (‘The Act’), and its subsequent amendment under the Climate Change (Emissions Reduction Targets) (Scotland) Act 2019, sets the framework for the Scottish Government to address climate change. The Act has an ambitious target to reach Net Zero greenhouse gas emissions by 2045, with any residual emissions balanced by removing carbon dioxide from the atmosphere. This is five years earlier than the rest of the UK due to the greater potential for carbon sequestration in Scotland.

The Act was amended to replace interim targets with carbon budgets. Carbon budgets are legally binding caps on greenhouse gas emissions in Scotland over five-year periods. In line with the Act, the Climate Change Committee (CCC) published advice on the level of Scotland’s four carbon budgets, covering the period 2026 to 2045, recommending what the Scottish Government sets its carbon budgets at for annual average levels of emissions. These recommendations are based on an ambitious but credible route to Net Zero for Scotland by 2045.

Emissions reductions from surface transport are the largest contribution to meeting the first two carbon budgets. The pathway for surface transport emission reduction is primarily driven by the uptake of electric vehicles, in addition to measures to enable a shift from car use to public transport and active travel, which all play a role in reducing emissions from fossil fuel cars. Ensuring efficiency of existing transport infrastructure and improving/providing new active travel facilities is therefore important to support these carbon reduction budgets.

Transport is the largest contributor to harmful climate emissions in Scotland. In response to the climate emergency, Transport Scotland are committed to reducing their emissions by 75% by 2030 and to the above noted legally binding target of net-zero by 2045. Transport Scotland is committed to reducing carbon across Scotland’s transport network and this commitment is being enacted through the Mission Zero for Transport (Mission Zero for transport | Transport Scotland).